Fuel injection pump

ABSTRACT

A fuel injection pump assembly in which fuel delivered from individual pump plungers is controlled by a pump drive shaft driven single control valve, the position of which, relative to the spill ports from the plungers, is controlled by means of a hydraulic governor and a flyweight-type advance mechanism.

Unite States Patent Knapc air. M, W72

[54] IFUEL INJECTION PUMP [56] Reierences Cited [72] Inventor: Richard S. Knape, Grand Rapids, Mich. UNITED STATES PATENTS 1 Assignw General Motors Corporation Detroit, 2,573,792 11/1951 .lakobsen ..123/139 Mlch- 3,319,568 5/1967 Repko et al ..123/140 x [22] Filed: July 6, 1970 D Primary Examiner-Laurence M. Goodrldge U pp No 1 52,391 Attorney-Jean L. Carpenter and Arthur N. Krein 152 11.s.c1. ..123/14o FG, 123/139 R, 123/139 13, [571 ABSTRACT l23/139 l23/139 A61 123/139 AP, 417/2931 A fuel injection pump assembly in which fuel delivered from 417/507 individual pump plungers is controlled by a pump drive shaft [5]] Int. Cl ..F02d 11/12 driven single control valve, the position f which, remive to [58] Field of Search ..l23/l39, 139 B, 139 AG, 139 AP, the Spill Ports f the plunges, is controlled by means f a 123/139 139 140 A, 140 hydraulic governor and aflyweight-type advance mechanism.

6 Claims, 6 Drawing Figures FUEL INJECTION PUMP This invention relates to a fuel injection pump and, in particular, to a fuel injection pump adapted to deliver metered amounts of fuel to fuel injection nozzles located in the cylinders of an internal combustion engine.

A primary object of this invention is to improve a fuel injection pump whereby fuel metering is controlled by a single control valve which is driven by the drive shaft of the pump and located with respect to the spill ports from the individual pump plungers by means of a hydraulic governor and by a flyweight type advance mechanism.

Another object of this invention is to provide an improved fuel injection pump whereby a hydraulic type all-speed governor operated by spill fuel is used to vary the fuel discharged to the fuel injectors of an engine as a direct function of engine speed and load conditions.

These and other objects of the invention are obtained by means of a fuel injection pump having a rotating cam plate, driven by a drive shaft, to operate a plurality of axially disposed pump plungers, and a drive shaft rotated control valve which selectively prevents spill from the plungers to provide fuel injection. Rotation of the control valve relative to the drive shaft to control timing is effected by means of an advance mechanism consisting of flyweights having pins extending therefrom which engage in slots in a drive plate having an adjustable driver thereon to drive the control valve through a pin and rod assembly, the latter being operatively connected to rotate the control valve while permitting relative axial movement therebetween. Speed control is effected by means of a hydraulic governor utilizing pressurized spill fuel to effect relative axial movement of the control valve against the biasing action of a governor spring, a throttle controlled variable sized orifice being used to regulate the discharge of spill fuel from the fuel injection pump assembly.

For a better understanding of the invention as well as other objects and further features thereof, reference is had to the following detailed description of the invention to be read in connection with the accompanying drawings, wherein:

FIG. 1 is a cross sectional view of the fuel injection pump of the invention;

FIG. 2 is a view taken along line 22 of FIG. 1 showing the details of the throttle valve assembly;

FIG. 3 is a sectional view taken along line 3--3 of FIG. 1 showing the details of the advance mechanism;

FIG. 4 is a view taken along line 4-4 of FIG. 1, with parts broken away to show details of the throttle valve assembly and the fuel inlet portion of the pump assembly;

FIG. 5 is a developed view of the cam contour to effect reciprocation of the pump plunger; and,

FIG. 6 is an enlarged developed view of the control valve of FIG. 1.

Referring now to FIG. 1, the fuel injection pump of the invention includes a pump housing assembly having a pump body 5 enclosing the pump plungers and a control valve, a throttle valve housing 6 and a control body 7 enclosing an advance mechanism, these elements being suitably secured together with a cam baseplate 8 and annular seal 9 sandwiched between the pump body 5 and control body 7.

A drive shaft 11, which would be driven through a suitable power takeoff from the engine is journaled at one end by bearing 12, positioned in a counterbored portion of the control body 7, the shaft being retained against axial displacement with respect to the bearing by means of a thrust race 13 and an annular retaining ring 14 positioned in a suitable annular groove provided in the drive shaft 11 for this purpose. At its opposite or upper end, the drive shaft 11 is rotatably sup ported by means of a bearing 15 positioned in the counterbored portion of the cam base plate 8. The upper end of the drive shaft 11 is provided with splines engaged with the internal splines provided on an annular cam 16 having an annular angle upper cam surface 16a to effect reciprocation of pump plungers by means of cam followers to be described in detail hereinafter.

The pump body 5 is provided with an axial bore 36 for a purpose to be described and circumferentially spaced through bores 17, the number of these bores corresponding to the number of engine cylinders to be supplied with fuel, in this embodiment six as shown in FIG. 4. Each of the bores 17 has slideably mounted therein at its lower end a tappet assembly including a cam follower rotatably supporting a cam follower ball 19 in engagement with the cam surface of cam 16, to effect reciprocation of a plunger 21 through plunger retainer 25. Each plunger 21 is reciprocably mounted in a plunger bushing 22 secured in the bore 17 by fitting 23, the lower end of which is threadingly engaged with the internally threaded upper end of the plunger bushing 22. The plunger 21 is normally biased downward as seen in FIG. 1 by means of a follower spring 24, one end of which is in engagement with a stepped portion of plunger bushing 22 and another end in engagement with notched plunger retainer 25, secured to an undercut portion of the plunger 21.

The fitting 23 is provided with an axial passage 26 in communication with intersecting radial passages 27 and with axial passage 28 via axial passage 29 for communication through injection tube 31 with a fuel injection nozzle, not shown, the injection tube 31 being secured to the fitting 23 by means of a ferrule 32 and tube coupling 33, the latter being threaded into the top of fitting 23. A ball 34 is positioned in passage 29 and is normally biased by spring 35 into seating engagement against a shoulder formed between passages 26 and 29. The ball 34 serves both as a check valve and a retraction valve as described hereinafter.

Fuel flow to and from the pump chambers, defined by plungers 21 in plunger bushings 22, and the: controlled discharge of fuel to the nozzles through the injection tubes is effected by means of a control valve housed in the pump body 5 and an advance mechanism housed in the control body 7.

A control valve sleeve 41, which can be formed as part of the pump body 5, or as shown, can be a separate element secured as by a shrink fit in the bore of pump body 5, has a through bore 46 therein closed at the outer end of the pump body by a cover plate 42 having a threaded aperture therein to adjustably receive a set screw 43 which can be locked in a desired position by locking nut 44. At its bottom end, as seen in FIG. 1, the set screw 43 is secured to one end of an annular stop 45 sealed against the through bore 46 in the control valve sleeve 41 by O-ring 47 positioned in a suitable annular groove provided for this purpose in the annular stop 45. At its opposite end, the annular stop supports: a stop ball 48 secured therein as by a press fit.

A control valve 49 is axially and rotatively movable within bore 46 of control valve sleeve 41 and forms with it an annulus or fuel storage chamber 51 filled with fuel entering by way of inlet 52, annulus 53 and longitudinal slot 54 in the outer portion of control valve sleeve 41 and holes 55 therein, as seen in FIG. 4. Inlet 52 is connected by a suitable conduit to a source of fuel, not shown. Radial passages 56 in sleeve 41 connected to passages 57 in the pump body 5, constitute spill holes or ports and also fuel inlets connecting chamber 511 to each pump chamber by annulus 58 aligned with the radial passages 27 in fitting 23.

Control valve 49, a spool-type valve, has both axial and rotational movement to variably close or open spill ports 56, the rotation of this valve 49 being properly phased to the plunger displacement as determined by the profile of cam surface 16a. Valve 49 has upper, middle and lower seal lands 61, 62 and 63, respectively, connected by necked portions 64 and 65 of reduced diameter to form with the control valve sleeve 41, a fuel spill chamber 66 and the previously identified fuel storage chamber 51. The land diameters are such as to effectively seal the annular internal fuel chambers defined between these lands so that axial movement of the valve will control fuel flow into and out of spill ports 56. Middle land 62 has interconnecting seal land portions 67 and 68 and an intermediate upturned seal land portion 69 therebetween, the latter in the form of a helix. These seal land portions form therebetween slots 71 and 72 in communication with spill chamber 66 for a purpose to be described.

Control valve 49 is operatively connected to the drive shaft 11 for rotation therewith by meansof a rod 73, with means, in the form of an advance mechanism, being associated with this rod to adjust the valve rotatively with respect to shaft 11 to control fuel injection timing relative to engine speed. As shown in FIG. 1, rod 73 has an upper flat portion or tangslideably engaged in the slotted lower end of the valve 49, the opposite end of the rod 73 being received in a bore in shaft 11. The rod 73 in turn is driven by means of a drive pin 74 extending radially therefrom through a suitable slot 75 in the drive shaft in position to be engaged by means of a driver 76 in the form of an adjustable set screw threaded into the drive plate 77 which is loosely positioned on the drive shaft for limited rotation relative thereto.

A base advance plate 78 is fixed to the shaft 11, as by a set screw 81 and pivotally supports a pair of flyweights 82 by means of shoulder pivot pins 83 secured therein to extend outward therefrom in parallel relation to the axis of the drive shaft 11. Each flyweight 82 is normally biased in a counterclockwise direction, as seen in FIG. 3, by means of a spring 84 connected at one end to the free end of a pivot pin 83 and at its opposite end to a post 85 secured to the flyweight in an overcenter position from the axis of the associated pivot pin 83 whereby the axially extending pin 86 on each flyweight extending in suitable slots 87 can effect relative movement of drive plate 77 and, therefore, valve 49 with respect to the drive shaft, in direct relationship to the rotative speed of the drive shaft as determined by engine speed.

Static timing of fuel injection is effected by means of the adjusting set screw or driver 76 which can be moved in or out relative to drive plate 77 to adjust the radial position of drive pin 74 so that the seal land 69 on valve 49 will close the spill port 56 associated with the fuel injection nozzle for the number one cylinder of the engine when this cylinder is on the compression stroke. Access to the adjusting set screw or driver 76 is through a suitable aperture provided in the control body 7 which is normally closed by a cover plate 88.

Rod 73 is normally biased in a counterclockwise direction, as seen in FIG. 3, with drive pin 74 in engagement with driver 76 by means of a torsion spring 91 encircling the rod with one end of the spring secured to the tanged portion of the rod 73 and the other end of the spring secured in a radially extending slot provided in the central boss of cam 16 which is fixed, as previously described, to shaft 11.

Fuel output at various engine speeds and fuel cutoff when the fuel injection pump exceeds a predetermined speed is controlled by means of a hydraulic governor and throttle arrangement which is used to provide a governing pressure in the spill chamber 66 and in the variable volume chamber 95 above the valve 49, as seen in FIG. 1. This governing fuel spill pressure acts against the valve 49 to move it in one direction, downward as seen in P16. 1, against the biasing action of a spring 92 which normally tends to move the valve in the opposite direction. Spring 92 is seated at one end against an annular stop collar 93 resting against the central boss of cam 16 and, at its other end the spring 92 engages a spring seat 94 encircling the reduced lower end of valve 49 and in engagement with a shoulder thereon.

Spill chamber 66 is connected by radial bore 96 and vertical bore 97 in control valve 49 to the control chamber 95 and, by passages 59 and 98 in the sleeve 41 and pump body 5, respectively, to an annular chamber 101 in the throttle valve housing 6. Throttle valve housing 6 is counterbored to form the chamber 101 and to rotatively receive a throttle valve 102 secured to a throttle lever 103 which is connectable through suitable linkage, not shown, for actuation by an operator. Throttle valve 102 is provided with an axial passage 104 in direct communication with chamber 101 and adapted to be placed in communication with the spill passage 106 in the throttle valve housing by means of a narrow metering slot 105 therein. The throttle valve 102 with the slot 105 therein forms with the wall of valve housing 6 and the spill passage 106 a variable size orifice, the size of which is controlled by throttle position for discharge of spill fuel into the spill passage from where it can be drained back to the fuel supply tank, not shown.

Chamber 101 is also connectable to spill passage 106 by means of a pressure release valve arrangement housed in the throttle valve housing 6. As shown in FIG. 2, a valve spring 107 biased ball 108 controls the flow of fuel from conduit 109 in communication with chamber 101 to passage 111 intersecting into spill passage 106. Spring retainer 112, threaded into the throttle valve housing is used to control the compression of valve spring 107 to vary the pressure required to unseat ball 108 as desired.

Before operating the fuel injection pump, the advance mechanism of this unit is statically timed and then operatively connected to a previously timed engine. Timing of the fuel injection pump per se is accomplished by rotating the drive shaft 11 so that a timing mark, not shown, on the base advance plate 78 directly opposite set screw 81 is lined up with the pointer 79 secured to cam base plate 8. Driver 76 in drive plate 77 is then adjusted to rotate valve 49 through drive pin 74 and rod 73 either clockwise or counterclockwise so that land 69 on valve 49 just covers the spill port 56 associated with the number one cylinder of the engine. This spill port closure adjustment can be conveniently accomplished while flowing fluid through this spill port so that when the land 69 covers the spill port, fluid flow will stop, indicating port closure.

With the fuel injection pump statically timed to the engine, the injection of fuel into each cylinder of the engine will occur at the proper time relative to the piston stroke in the cylinder. The timing while the engine is operating will be automatically changed by means of the flyweights 82. In the particular embodiment of the fuel injection pump shown, the advance mechanism thereof provides for an automatic advance, that is, fuel injection occuring earlier in the engine cycle, of 10 at an engine speed of 3,200 revolutions per minute. At speeds of from 0 to 800 revolutions per minute, fuel injection will occur per the static timing just described since the springs 84 will keep the flyweights in their inward position as shown in FIG. 3. At an engine speed of 800 revolutions per minute, the automatic advance begins and progresses to the 10 advance at an engine speed of 3,200 revolutions per minute. This automatic advance is approximately linear with speeds between 800 and 3,200 revolutions per minute and is effected by the flyweights 82 swinging outward due to centrifugal force causing the drive plate 77 to rotate relative to the drive shaft 11, thus rotating valve 49 relative thereto to produce a change in spill port closure timing causing a change in the timing of the fuel entering the combustion chambers.

Although a particular embodiment of the advance mechanism has been disclosed, it is to be realized that this advance mechanism can be designed to produce any degree of advance or retard depending on the specific engine requirements. It is also to be realized that such an automatic advance mechanism would not be required for some engine designs.

In operation, the fuel injection pump of the invention delivers a metered amount of fuel to the fuel injection nozzles located in the cylinders of an engine and is driven by the engine at a proper speed relative to the type of engine on which the fuel injection pump is used. For'a two-cycle engine, the drive shaft of the pump would rotate at engine speed and for a four'cycle engine, it would rotate at engine camshaft speed.

The fuel injection pump of the invention requires no internal or external supply pump to charge the pump chambers after an injection stroke, as is commonly required in other known types of fuel injection pumps. This is made possible by providing the control valve with seal lands to separate spill fuel from the inlet fuel to the pump chambers and by a properly designed profile for cam 16 to provide for a constant drop per degree to effect a low velocity return of the plungers 21 during the suction stroke.

Referring to FIGS. 1, 4, 5 and 6, the latter two figures illustrating preferred valve land and cam profiles, fuel enters the fuel chamber 51 by way of inlet 52, annulus 53, slots 54 and the holes 55 in sleeve 41. Whenever a tappet assembly, cam follower 18 and ball 19, of a plunger assembly is on its return stroke, that is, 85 to 325 as shown in FIG. 5, the spill port 56 associated with that plunger and tappet assembly communicates with the fuel chamber 51 and, due to the downstroke of the tappet assembly and its associated plunger 21, fuel is drawn under suction from the fuel chamber into the pump chamber. At the end of the return stroke which is at the cam angle of 325, as shown in FIG. 5, the pump chamber has been charged with fuel and is ready for the injection and spill stroke cycle of the plunger 21. As the cam 16 and valve 49 rotate with the cam 16 rotating from 325 to 0, the land 67 of valve 49 crosses over the spill port 56. From 0 to 45, the cam lift portion of cam 16 will cause upward movement of the plunger 21. From 0 to approximately 20 of cam rotation, the plunger 21, during its upward movement, spills fuel into the slot 71 which communicates with spill chamber 66. From 20 to depending on the axial position of valve 49, the spill port 56 is covered by land 69 causing fuel to be pumped out through injeetion tube 31 to the fuel injection nozzle for discharge into an engine cylinder. From 25 to 45 of cam rotation, the plunger 21 will cause fuel to spill into slot 72 which now overrides the spill port 56, this fuel being discharged into spill chamber 66. From 45 to 85 of cam rotation, land 68 will cross the spill port 56 after which the spill port again comes into communication with fuel chamber 51 for the return or fill stroke, as previously described. Seal lands 67 and 68, prevent spill fuel from entering the fuel chamber 51, thus allowing a steady suction pressure to be maintained in the fuel inlet system, as previously described, as effected by the suction strokes of the individual plungers.

In the embodiment of the fuel injection pump disclosed, at any one time there are four spill ports communicating with the fuel chamber 51 and therefore, four plungers 21 on the suction or return stroke. The seal lands 67 and 68 and middle land 62 provide with the upper land 61 and the peripheral inner surface of valve sleeve 41, the spill chamber 66 in which is collected the spill fuel. Spill fuel can flow from spill chamber 66 to control chamber 95 to act on the upper end of control valve 49 against the biasing action of spring 92 in a manner to be described. From the above description, it is apparent that the seal lands of control valve 49 serve as a valving means to control inlet flow to the pump chambers and as a means for collecting fuel spill flow used to actuate the hydraulic speed governor.

During the fuel injection portion of the plunger pumping stroke, as previously described, fuel is delivered under pressure through the associated injection tube 31 to a fuel injector nozzle for discharge into the engine cylinder. As is well known, the fuel injector nozzle generally has a set opening pressure below which no fuel is discharged from the nozzle. Once the nozzle of the fuel injector opens and a predetermined quantity of fuel has been ejected therefrom, the pressure drops and the valve therein regulating fuel injection closes. The residual pressure in the fuel injector and the injection tube is then substantially the same as the closing pressure unless a retraction valve is used in the discharge conduit from the fuel injection pump to the fuel injection nozzle. These retraction valves operate on a retraction principle, that is, the principle of retracting a finite volume of fuel from the fuel line to reduce the residual pressure in the fuel line between the pump plunger and the injection nozzle so that secondary injection of fuel will not occur.

Referring again to FIG. 1, the ball 34 in fitting 23 serves both as a check valve and as a retraction valve. In operation, the ball 34 is normally seated, as shown, due to the biasing action of spring 35 and the residual fuel pressure in the injection tube 31 and the fuel injection nozzle. In this position, the ball 34 serves as a check valve holding some residual fuel pressure in the injection tube and associated nozzle. During the fuel pumping cycle, fuel from the pump chamber forces the ball 34 off its seat and then acts on the external diameter of the ball to cause a more rapid movement of the ball upward in axial passage 29, as seen in this figure. Since the clearance between the ball 34 and the wall of passage 29 is small, the ball must move a short distance upward into passage 28 in order to allow for adequate fuel flow to the injection tube 31 and its associated nozzle. When the spill port 56 is placed in communication with the spill chamber 66 by rotation of the valve 49, as previously described, the fuel pressure on the plunger side of the ball 34 lowers quickly and the fuel pressure in the injection tube plus the biasing action of spring 35 returns the ball to its seat, as shown. As the outside diameter of the ball passes the edge of the shoulder between passages 20 and 29, it retracts fuel from the passage 23 and therefore, from the injection tube 31 to cause a rapid drop in fuel pressure in the injection tube, causing the injection nozzle to close quickly. This retraction volume is considered to be a volume defined by the ball travel times the cross-sectional area of the ball 34.

The hydraulic governor unit of the fuel injection pump is used to maintain idle speed of the engine, to control fuel output to the fuel injection nozzles from idle to maximum engine speed and, to cut off fuel flow to the fuel injection nozzles when the pump speed exceeds a predetermined speed. Spill fuel from the pump plungers is used as the speed sensing element permitting this hydraulic governor to operate as an all speed governor.

As previously described, the hydraulic governor includes a throttle valve 102 having a metering slot 105 therein to provide a variable size orifice, the size of which is a function of throttle lever 103 position. Fuel spill from the spill ports 56 into the spill chamber 66 flows through bores 96 and 97 in valve 49 into the control chamber wherein the spill fuel pressure is applied to the top end, as seen in FIG. 1, of the control valve 49, this pressure being resisted by the spring 92 which is preloaded so that a definite pressure level in the control chamber 95 is required to start the downward movement of the control valve as viewed in FIG. 1. Downward movement of the control valve causes lower fuel output to the fuel injection nozzle due to the helix angle of the trailing edge of seal land 69, in terms of valve 49 rotation.

When the throttle lever 103 is in idle position, against an idle stop, not shown, the orifice formed by slots 105 in throttle valve 102 is the smallest of any throttle setting and when the throttle lever 103 is in the wide open throttle position, against a suitable wide open stop, not shown, the size of the orifice is at maximum.

While the fuel injection pump is not. in operation, spill fuel remaining in spill chamber 66 and control chamber 95 will slowly drain back through the variable size orifice for discharge through the spill passage 106 in the throttle valve housing, the fuel being forced out of control chamber 95 by upward movement of valve 49, as seen in FIG. 1, by the spring 92.

Thus, when the fuel injection pump is ready to operate again, the spring 92 will have moved the control valve 49 upward against the stop ball 48. In this position of the control valve 49, the lower widest portion of the seal land 69 is in position to sequentially cover the spill ports 56 as the valve is rotated so that the maximum quantity of fuel is delivered to the fuel injection nozzles when the engine is started. I

Now, if operation of the fuel injection pump is initiated and the operator has set the throttle lever 103 at the idle position, the size of the orifice in the throttle valve is the smallest of any throttle setting. As the pump is operated, fuel will spill into the spill chamber with the pressure of the spill fuel increasing until such time that its pressure is sufficient to push the control valve 49 downward by spill fuel entering control chamber 95 against the biasing action of spring 92 until the seal land 69 is in the required position to meter idle fuel quantities. If the engine speeds up, due to a loss of load, the fuel injection pump will operate at a higher speed directly related to engine speed so that the spill fuel quantity will increase causing a rise in a control spill fuel pressure to cause the control valve 49 to move further downward, in terms of FIG. 1, with a narrower portion of the seal land 69 now covering the spill ports 56 thereby reducing the quantity of fuel delivered to the engine. This reduction of fuel to the engine causes the engine to slow down.

If, on the other hand, the engine speed drops below the governed speed, as set by the throttle lever position, the amount of spill fuel decreases with a related decrease in the control pressure so that the governor spring 92 will overcome the spill fuel pressure to move the control valve upward, in terms of FIG. 1, to again increase the amount of fuel delivered to the engine. This increase of fuel will then cause the engine to speed up back to the governed speed condition as set by the throttle valve.

Then, if the operator opens the throttle 103 to the wide open position, the size of the orifice opening in the throttle valve is increased allowing spill fuel to drain more rapidly from the spill chamber 66 and control chamber 95 permitting the control pressure of the spill fuel to drop to a pressure below the force of spring 92 allowing the spring 92 to move the control valve 49 upward to a maximum fuel position at which position it will remain until the engine speed reaches a predetermined cutoff speed as determined by the contour and length of the seal land 69. At this predetermined cutoff speed, the amount of spill fuel will be such so that the pressure in the control chamber 95 will just balance the force of spring 92 to maintain the engine operating at this predetermined cutoff speed. If, for some reason the speed of the engine increases above the predetermined cutoff speed, spill fuel pressure will again increase to start moving the control valve 49 downward causing fuel cutoff, and thereby limiting the maximum speed in which the engine can operate. At any part throttle position, the operation is similar and governing will take place just as at idle or wide open throttle position.

In the embodiment of the fuel injection pump assembly disclosed, the hydraulic governor and advance mechanisms are separate from each other even though they both control a common part, the control valve 49. This feature of the construction allows independent adjustment or changes in either the hydraulic governor or in the advance mechanism to suit a particular engine application. With this arrangement, the fuel injection pump can properly schedule fuel delivery to an internal combustion engine during the entire speed and load range of operation of the engine.

What is claimed is:

l. A fuel injection pump comprising, in combination, housing means having a central bore closed at one end and a conduit in communication with said bore and connectable to a source of fuel, a plurality of pumping means each having a fluid passage connected to a fuel discharge line and to a fuel spill passage, each of said fuel spill passages being in communication with said bore, a drive shaft journaled in said housing and operatively connected to said pumping means, a speed responsive hydraulic governor controlled metering means including a speed responsive means and a metering valve, said metering valve being slideably and rotatably mounted in said bore, said metering valve having fluid control portions thereon operable in said bore to form therewith a fluid supply chamber in communication with said conduit, a fluid spill chamber, and a control chamber at one end of said fluid metering valve adjacent to and in communication with said fluid spill chamber, said fluid spill chamber and said control chamber being connectable to the source of fuel bypassing said fluid supply chamber, said fluid control portions including a metering helix portion cooperable with said fuel spill passages to control the flow of fluid therefrom, and a central portion separating said supply chamber from said fluid spill chamber to control the flow of fluid from said supply chamber to said spill passages and the discharge of fluid from said spill passages to said spill chamber, and said speed responsive means slideably connecting said metering valve to said drive shaft for rotation therewith and for effecting limited rotation of said metering valve relative to said drive shaft.

2. A fuel in ection pump according to claim 1 wherein said speed responsive hydraulic governor controlled metering means includes biasing means connected to said metering valve for normally moving said metering valve axially in one direction and a throttle valve in fluid communication with said control chamber and directly with the source of fuel bypassing said conduit and said supply chamber to regulate the pressure of fluid in said control chamber acting on said metering valve against the biasing action of said biasing means.

3. A fuel injection pump according to claim 1 wherein said speed responsive means includes coupling means positioned coaxially relative to said drive shaft and slideably secured to said metering valve, drive means rotatably supported on said drive shaft in driving engagement with said coupling means, a flyweight governor means secured to said shaft for rotation therewith, said flyweight governor means including a pair of flyweights operatively connected to said drive means to rotate said coupling means through said drive means with said drive shaft and relative thereto in a first direction and spring means operatively connected to said coupling means to rotate said coupling means relative to said drive shaft in a second direction.

4. A fuel injection pump comprising, in combination, housing means having a centralbore closed at one end to form a valve sleeve and a conduit in communication at one end with said valve sleeve and connectable at its other end to a source of fuel, a plurality of pumping means equally spaced radially around said bore, each of said pumping means having a pump chamber connected to a fuel spill passage in communication with said bore, and to a fuel discharge conduit, a drive shaft journaled in said housing and operatively connected to said pumping means, a fluid control valve axially and rotatively journaled in said sleeve, speed responsive means slideably connecting said fluid control valve to said drive shaft for rotation therewith and for limited rotation relative thereto, biasing means connected to said control valve for biasing said control valve in one direction, said fluid control valve having fluid control portions thereon operable in said sleeve to form therewith a fluid supply chamber in communication with said conduit, a fluid spill chamber and, a control chamber between one end of said fluid control valve opposite said biasing means and adjacent to the closed end of said sleeve, said fluid flow portions including a portion between said fluid supply chamber and said fluid spill chamber controlling the flow of fuel into said spill passages from said fluid supply chamber and variably controlling the flow of fluid from said spill passages to said spill chamber and passage means in said fluid control valve connecting said spill chamber and said control chamber and throttle controlled variable size orifice means positioned to control the discharge of fluid from said fluid spill chamber to the source of fuel and bypassing said conduit and said fluid supply chamber to thereby control the pressure of fluid in said control chamber acting on said control valve against the force of said biasing means.

5. A fuel injection pump according to claim 4 wherein said means slideably connecting said fluid control valve to said drive shaft includes torsion means to normally rotatively bias said control valve in one direction with respect to said drive shaft and a speed responsive advance mechanism driven by said drive shaft for driving said control valve and for effecting limited relative rotational movement of said control valve with respect to said drive shaft as a function of the rotational speed of said drive shaft.

6. A fuel injection pump according to claim 5 wherein said speed responsive advance mechanism includes flyweights operatively connected to said drive shaft and spring means normally biasing said flyweights to an inoperative position with respect to said control valve. 

1. A fuel injection pump comprising, in combination, housing means having a central bore closed at one end and a conduit in communication with said bore and connectable to a source of fuel, a plurality of pumping means each having a fluid passage connected to a fuel discharge line and to a fuel spill passage, each of said fuel spill passages being in communication with said bore, a drive shaft journaled in said housing and operatively connected to said pumping means, a speed responsive hydraulic governor controlled metering means including a speed responsive means and a metering valve, said metering valve being slideably and rotatably mounted in said bore, said metering valve having fluid control portions thereon operable in said bore to form therewith a fluid supply chamber in communication with said conduit, a fluid spill chamber, and a control chamber at one end of said fluid metering valve adjacent to and in communication with said fluid spill chamber, said fluid spill chamber and said control chamber being connectable to the source of fuel bypassing said fluid supply chamber, said fluid control portions including a metering helix portion cooperable with said fuel spill passages to control the flow of fluid therefrom, and a central portion separating said supply chamber from said fluid spill chamber to control the flow of fluid from said supply chamber to said spill passages and the discharge of fluid from said spill passages to said spill chamber, and said speed responsive means slideably connecting said metering valve to said drive shaft for rotation therewith and for effecting limited rotation of said metering valve relative to said drive shaft.
 2. A fuel injection pump according to claim 1 wherein said speed responsive hydraulic governor controlled metering means includes biasing means connected to said metering valve for normally moving said metering valve axially in one direction and a throttle valve in fluid communication with said control chamber and directly with the source of fuel bypassing said conduit and said supply chamber to regulate the pressure of fluid in said control chamber acting on said metering valve against the biasing action of said biasing means.
 3. A fuel injection pump according to claim 1 wherein said speed responsive means includes coupling means positioned coaxially relative to said drive shaft and slideably secured to said metering valve, drive means rotatably supported on said drive shaft in driving engagement with said coupling means, a flyweight governor means secured to said shaft for rotation therewith, said flyweight governor means iNcluding a pair of flyweights operatively connected to said drive means to rotate said coupling means through said drive means with said drive shaft and relative thereto in a first direction and spring means operatively connected to said coupling means to rotate said coupling means relative to said drive shaft in a second direction.
 4. A fuel injection pump comprising, in combination, housing means having a central bore closed at one end to form a valve sleeve and a conduit in communication at one end with said valve sleeve and connectable at its other end to a source of fuel, a plurality of pumping means equally spaced radially around said bore, each of said pumping means having a pump chamber connected to a fuel spill passage in communication with said bore, and to a fuel discharge conduit, a drive shaft journaled in said housing and operatively connected to said pumping means, a fluid control valve axially and rotatively journaled in said sleeve, speed responsive means slideably connecting said fluid control valve to said drive shaft for rotation therewith and for limited rotation relative thereto, biasing means connected to said control valve for biasing said control valve in one direction, said fluid control valve having fluid control portions thereon operable in said sleeve to form therewith a fluid supply chamber in communication with said conduit, a fluid spill chamber and, a control chamber between one end of said fluid control valve opposite said biasing means and adjacent to the closed end of said sleeve, said fluid flow portions including a portion between said fluid supply chamber and said fluid spill chamber controlling the flow of fuel into said spill passages from said fluid supply chamber and variably controlling the flow of fluid from said spill passages to said spill chamber and passage means in said fluid control valve connecting said spill chamber and said control chamber and throttle controlled variable size orifice means positioned to control the discharge of fluid from said fluid spill chamber to the source of fuel and bypassing said conduit and said fluid supply chamber to thereby control the pressure of fluid in said control chamber acting on said control valve against the force of said biasing means.
 5. A fuel injection pump according to claim 4 wherein said means slideably connecting said fluid control valve to said drive shaft includes torsion means to normally rotatively bias said control valve in one direction with respect to said drive shaft and a speed responsive advance mechanism driven by said drive shaft for driving said control valve and for effecting limited relative rotational movement of said control valve with respect to said drive shaft as a function of the rotational speed of said drive shaft.
 6. A fuel injection pump according to claim 5 wherein said speed responsive advance mechanism includes flyweights operatively connected to said drive shaft and spring means normally biasing said flyweights to an inoperative position with respect to said control valve. 